GREEK FIRE. This compound, so much used in ancient warfare, is believed to have had naphtha for its chief ingredient. According to some authorities, it was a mixture of asphalt, nitre, and sulphur.
GREGORY’S SALT. The crude hydrochlorate of morphia, prepared by Gregory’s process. It is a double hydrochlorate of morphia and codeia.
GRINDELIA ROBUSTA. A perennial plant belonging to the natural order Compositæ; a native of California, in which state it is largely used against poisoning by the “poison oak” (the Rhus toxicodendron). Of late years it is said to have been in American medical practice used with excellent effect in asthma and kindred diseases. Dr Q. C. Smith, writing to the ‘Pacific Medical and Surgical Journal’ for April, 1875, states one patient to whom pills made of the solid extract were administered, had suffered from severe and frequent attacks of asthma since childhood, and had found no relief from various remedies. Dr Smith gave his patient the extract of the grindelia in pills of three grains each, one three times a day for two or three days, then a pill at bedtime only, for eight or ten days longer. Under this mode of treatment the attacks are said to have been much less severe, and less frequent; the patient not only gaining in strength and general health in the meantime, but having experienced an immunity from attack for four months. The parts of the plant used are the selected leaves and tops.
GRIND′ING. The operation of reducing substances to powder by attrition or friction. In the laboratory, the term is chiefly applied to powdering by means of a mill or by mechanical power, in opposition to simple pounding or trituration in a mortar or with a slab and muller. All the principal powders, paints, &c., sold by the druggist, drysalter, and colourman, are reduced in the drug or colour mill. Recently machinery has even been applied to the common mortar. An ingenious and very useful
contrivance of this kind is the ‘mechanical mortar’ of Mr H. Goodhall, of Derby.
GRIND′STONES. (Artificial). Washed siliceous sand, 3 or 4 parts; shell-lac, 1 part; melt together, and form the mass into the proper shape whilst warm, with strong pressure. The fineness of the sand must depend on the work the stone is intended for. The same composition is formed upon pieces of wood, as corn rubbers, and for the purpose of sharpening knives, and cutting stones, shells, &c. See Emery.
GROATS. Syn. Grits; Grutellum, Avena decorticata, Avenæ semina, Avena (Ph. L.), L. Common oats, deprived of their exterior integuments or husks. This is generally effected in a mill, which, at the same time, cuts them into two or three pieces. When crushed flat, they are denominated Embden groats.
GROUT. Mortar reduced to a thin paste with water, used to fill up the joints of masonry and brickwork. A finer kind is used to ‘finish off’ the best ceilings.
GRUEL. Syn. Oatmeal gruel, Water g.; Decoctum avenæ, L. Oatmeal or groats boiled with water to a proper consistence, and strained. It is variously flavoured to suit the palate; but the addition of a little white sugar, and finely powdered Jamaica ginger, with or without a glass of wine, is the least likely to offend the stomach. Nutmegs, cinnamon, &c., frequently disagree with invalids. Sometimes milk or butter is added. Embden groats require less boiling than the common groats. Of oatmeal, the Scotch is commonly said to be the best.
The following directions for making gruel from oatmeal are given by Dr A. T. Thomson: “Oatmeal, 2 oz.; cold water, 11⁄2 pint; rub the meal in a basin, with the back of a spoon, in some of the water, pouring off the fluid after the grosser particles have subsided, but whilst the milkiness remains; repeat this with fresh water, unite the washings, and boil until a soft, thick mucilage is formed.”